Data storage devices store digital information on a rotating disc or data storage medium. Data storage devices include a head having a transducer element to read data from or write data to the disc or data storage medium. Heads are coupled to a primary or first actuator assembly which is energized to position the head relative to the disc surface for read-write operations. The primary actuator is coupled to a servo control system to provide head position control. Areal density is increasing requiring improved position control. In particular, as tracks per inch increase, track positioning error must decrease.
Secondary actuators or microactuators have been proposed to improve track misregistration or track positioning. Typically, the secondary actuator or microactuator moves the head over a smaller stroke or displacement to provide micropositioning for dual stage actuation. The primary, or first actuator, and the secondary actuator, or microactuator, collectively provide head positioning. Control system architectures for single actuation devices are not designed to optimize servo control for the secondary actuator or microactuator relative to system constraints. Embodiments of the present invention provide solutions to these and other problems, and offer other advantages over the prior art.